Type 1 diabetes mellitus (T1D) management requires a significant effort by patients and their families to maintain near-normal glycemia. The effort is magnified when patients are young children. Recent technology development, integrated with advanced control design, has proven effective for improving diabetes managements in adults. However, the design of a pediatric artificial pancreas, focusing specifically on requirements of young children with T1D, and their parents, is in early stages and not yet been thoroughly investigated. We will focus on the design and clinical evaluation of a pediatric artificial pancrea system for enhanced diabetes management in young children with T1D. The ultimate goal of the project is to develop, and demonstrate in clinical studies, a safe and effective glucose management system that improves glucose outcomes in young children with T1D, and improves parental quality of life. Phase 1 - Development, refinement, and evaluation of pediatric glucose control strategy - pediatric artificial pancreas: Insulin/Carbohydrate on Board (IOB/COB) models for young children with T1D will be characterized and employed as safety mechanisms within a zone Model Predictive Controller for automatic insulin delivery. The controller will undergo preliminary clinical evaluation, with emphasis on assessing overnight and meal-time glucose control. Phase 2 - Design and evaluation of parental oriented remote advisory and glucose supervision system for open and closed-loop glucose control: We will engineer a parental remote supervision and alert system to reduce the risk of hypoglycemia, and the fear of nocturnal hypoglycemia, and develop adaptive advisory algorithms for glucose control, thereby improving insulin management by parents of young children with T1D. The alert and advisory system will be evaluated in a series of CRC and ambulatory clinical trials for safety and efficacy, as well for its effects on mitigating parental stress and anxiety. Phase 3 - Reduction of nocturnal hypoglycemia events and parental stress and improvement in glycemic control in ambulatory settings: The integrated system will be validated in a pilot clinical trial prior to deployment int practice, and contrasted, by a randomized crossover trial, with the state-of-the-art therapy; sensor augmented pump (SAP) or threshold suspend (TS) technology. The hypothesis of phase 3 is: Compared to SAP or TS, combining a pediatric AP and safety system reduces the hypoglycemia risk and lengthens time spent in the range 70-180 mg/dL, without compromising average glycemic control. Secondary outcomes include the system's effect on parental stress, anxiety, and fear of hypoglycemia.